[Sema] NFC: Print CanBindToPack type variable option in debug output

Author: xedin

lib/Sema/TypeCheckConstraints.cpp

@@ -67,6 +67,8 @@ void TypeVariableType::Implementation::print(llvm::raw_ostream &OS) {
     bindingOptions.push_back(TypeVariableOptions::TVO_CanBindToNoEscape);
   if (canBindToHole())
     bindingOptions.push_back(TypeVariableOptions::TVO_CanBindToHole);
+  if (canBindToPack())
+    bindingOptions.push_back(TypeVariableOptions::TVO_CanBindToPack);
   if (!bindingOptions.empty()) {
     OS << " [allows bindings to: ";
     interleave(bindingOptions, OS,